topic Re: User input for command flags in Operating System - Linux

User input for command flags

Vic S. Kelan — Tue, 12 Feb 2008 14:53:22 GMT

I am trying to set up a shell script that will prompt a user to enter a date and a second parameter.

For example if the command is:

-t '02/12/08' -q 'group=MY_GROUP'

What can I do to get the user to input the date he/she wants and keep it in the above format (MM/DD/YY) and also get prompted to enter the group name?

Any help will be appreciated very very much!

Re: User input for command flags

James R. Ferguson — Tue, 12 Feb 2008 15:13:55 GMT

Hi Vic:

Since your example is the standard switch-plus-argument format, you should consider using 'getopts()' to parse the switches and arguments.

http://docs.hp.com/en/B3921-60631/getopts.1.html

You are going to have to examine and verify the argument for "correctness" thereafter. For example, a valid date in the format shown would have a one or two digit month in the range 1-12. Similarly, you will have to define what constitutes a valid argument for '-q'.

Using regular expressions with 'grep' or 'awk' will help in the date validation, although you could simply 'cut' the field into pieces and make appropriate verifications to do that.

Regards!

...JRF...

Re: User input for command flags

Vic S. Kelan — Tue, 12 Feb 2008 16:09:26 GMT

Thanks JRF, I am not very familiar with the getopts and could not figure out how to use it from the man, actually very rusty with scripts. Do you have an example that could lead me on my way and I take it from there?

Thanks!

Re: User input for command flags

David Bellamy — Tue, 12 Feb 2008 17:07:51 GMT

This is something that i put together in perl, hope this helps.

#!/usr/bin/perl
use strict;
use diagnostics;
use warnings;

my $group;
print "Please Enter Date in the format MM/DD/YY: ";
my $date=;
chomp($date);
while() {
if($date=~/[0-1][0-9]\/[0-3][0-9]\/\d\d/) {
print "Please Enter Group Name: ";
$group=;
exit(0);
}else{
print "Invalid Date\n";
print "Please Enter Date in the format MM/DD/YY: ";
$date=;
}
}

Re: User input for command flags

James R. Ferguson — Tue, 12 Feb 2008 17:46:51 GMT

Hi (again) Vic:

This should get you started:

# cat .example
#!/usr/bin/sh
while getopts t:q: THINGS
do
case ${THINGS} in
t)
OPT_T=1
VAL_T=${OPTARG}
;;
q)
OPT_Q=1
VAL_Q=${OPTARG}
;;
?)
printf "Usage: %s: [-t date] [-q value]\n" $0
exit 2;;
esac
done
if [ ! -z "${OPT_T}" ] ; then
printf "Option -t with %s\n" ${VAL_T}
fi
if [ ! -z "${OPT_Q}" ] ; then
printf "Option -q with %s\n" ${VAL_Q}
fi
shift $(( $OPTIND -1 ))

if [ $# = 0 ]; then
print "No arguments remain"
else
printf "Arguments remaining: %s\n" "$@"
fi
exit 0

# ./example -q group=mine -t 02/12/2008 myfile
Option -t with 02/12/2008
Option -q with group=mine
Arguments remaining: myfile

Regards!

...JRF...

Re: User input for command flags

Vic S. Kelan — Wed, 13 Feb 2008 22:41:29 GMT

Thanks guys, this really helped!